const delete_unused_keys: Function = (res: any[], keys?: string[]): any[] => {
  let keyList = keys || ['_id', '_del']
  for (let i = 0; i < res.length; i++) {
    for (let j = 0; j < keyList.length; j++) {
      delete res[i][keyList[j]]
    }
  }
  return res
}

export default delete_unused_keys